Possibility to determine clashing atoms?

Dear all,

imagine you have any dimer consisting of subunits A and B whereas A is partially in contact with B.

Furthermore, let's assume that you have superimposed any other subunit (from a different PDB file),

let's say C, on B and visualizing solely C and A in DS using CPK "looks good/fits pretty well". Anyways.

My question is: Is there any possibility in DS (free version) to determine whether there are atomic

clashes between A and C (e. g. by breaking vdW radii)? If so, how can I determine/visualize them?

Thanks a lot in advance,

Gerd